The medical diagnostics industry is a critical element of today's healthcare infrastructure. At present, however, diagnostic analyses no matter how routine have become a bottleneck in patient care. There are several reasons for this. First, there are usually several steps in a diagnostic analysis between collecting the sample, and obtaining a diagnostic result, that require different levels of skill by operators, and different levels of complexity of equipment. For example, a biological sample, once extracted from a patient, must be put in a form suitable for a processing regime that typically involves using polymerase chain reaction (PCR) to amplify a nucleotide of interest. Once amplified, the presence of a nucleotide of interest in the sample needs to be determined unambiguously. Sample preparation is a process that is susceptible to automation but is also relatively routinely carried out in almost any location. By contrast, steps such as PCR and nucleotide detection have customarily only been within the compass of specially trained individuals having access to specialist equipment. Second, many diagnostic analyses can only be done with highly specialist equipment that is both expensive and only operable by trained clinicians. Such equipment is found in only a few locations—often just one in any given urban area. This means that most hospitals are required to send out samples to these locations for analysis, thereby incurring shipping costs and transportation delays, and possibly even sample loss, or mix-up. Third, some specialist equipment is typically not available ‘on-demand’ but instead runs in batches, thereby delaying the processing time for many samples because they must wait for a machine to fill up before they can be run.
The analysis of a biological sample to accomplish a particular diagnosis typically includes detecting one or more polynucleotides present in the sample. One example of detection is qualitative detection, which relates, for example, to the determination of the presence of the polynucleotide and/or the determination of information related to, for example, the type, size, presence or absence of mutations, and/or the sequence of the polynucleotide. Another example of detection is quantitative detection, which relates, for example, to the determination of the amount of polynucleotide present. Detection may therefore generally include both qualitative and quantitative aspects. Detecting polynucleotides qualitatively often involves establishing the presence of extremely small quantities in a sample. In order to improve sensitivity, therefore, the amount of polynucleotide in question is often amplified. For example, some detection methods include polynucleotide amplification by polymerase chain reaction (PCR) or a related amplification technique. Such techniques use a cocktail of ingredients, including one or more of an enzyme, a probe, and a labeling agent. Therefore, detection of polynucleotides can require use of a variety of different reagents, many of which require sensitive handling to maintain their integrity, both during use, and over time.
Understanding that sample flow breaks down into several key steps, it would be desirable to consider ways to automate as many of these as possible, and, desirably, to facilitate accomplishing as many as possible with a single machine that can be made available, on demand, to many users. There is therefore need for a method and apparatus of carrying out steps of sample preparation, PCR, and detection on biological samples in such a way that as few separate steps as possible are carried out.
The discussion of the background to the technology herein is included to explain the context of the technology. This is not to be taken as an admission that any of the material referred to was published, known, or part of the common general knowledge as at the priority date of any of the claims.
Throughout the description and claims of the specification the word “comprise” and variations thereof, such as “comprising” and “comprises”, is not intended to exclude other additives, components, integers or steps.